A low profile triband coupled resonator filtering antenna for wireless applications

This paper presents the design, realization, and performance analysis of a fixed triband coupled resonator filtering antenna. A wideband circular monopole antenna serves to be the radiating element, and a composite resonator comprising a meander-loop and two open-loop resonators is used as filtering element. With a view to integrate filtering and radiation functions in a single module, the composite resonator is fixed on the feedline of the wideband circular monopole antenna. The resonator is placed in an optimized position in the antenna feedline ensuring maximum current to the radiating structure and thereby rendering a low loss and miniaturized filtering antenna. The filtering antenna functions at three operating bands at centre frequencies: 2.4, 4.8, and 5.2 GHz; a reflection coefficient of less than 20 dB is achieved in each band. The gain is approximately 3 dBi across the three operating bands. A low-loss and compact triband filtering antenna having measurements 60 × 30 mm suitable for WLAN and Wi-Fi applications is realized.